How to get 5" TFT LCD working with STM32H7A3 using LTDC and CubeIDE

[JNguyen]

I have STM32H7A3ZIQ Nucleo board and 5" Startek LCD KD050FWFPA011. I'd like to use CubeIDE to create code to copy an image from H7A's flash memory to the LCD using LTDC. I did get STM32H7A3ZIQ Nucleo to work with a 2" LCD using 4-wire SPI interface. The problem I have with 5" LCD is the LTDC interface. Attached is IOC file, CubeIDE code, init code from Startek, scope captures, etc.... Please help.

I got black screen. Backlight is on. IDE reports the image (Mushroom480x800) is defined but not used. Scope captures show 0x00 on pin LTDC_R4. LTDC_CLK is 24MHz, correct as designed. What do I miss?

[JNguyen]

5" LCD spec.

[MM..1]

For use LCD you need some step and condition meet. Show image is last step...

Try explain what is problem , is your lcd init accepted, can command to lcd show white lcd usw...

From Nucleo you need for RGB24 connect to LCD around 30 high speed signals ...

[JNguyen]

There are 3 areas problems could exist in: 1) LCD initializing, 2)wiring between nucleo board and LCD, and 3)configuring/using LTDC. I have double checked the 1st two areas and haven't found any problem. I'm still working with LCD manuf in those areas. For now, the area I need help the most from ST is the 3rd one (LTDC). So I would much appreciate if anyone could review the IOC and code to see if I miss anything (most likely), and provide detail instructions. I have read documents/sample code about LTDC I could find, but still couldn't get it to work.

Connection between nucleo and LCD is per the IOC file and attached schematics.

[MM..1]

All except layer config seems good. LTDC layer is window onj display managed with memory framebuffer.

You in code need reserve memory and set it in Layer 0 - Color Frame Buffer Start Adress

When your config for layer is 565 then for example image 100x100 need 20000bytes .

I recomend start with internal memory and set 0 to 99 x and y ... Finaly this window is full LCD, but first step is simpler with small window.

Good is read LTDC appnote LCD-TFT display controller (LTDC) on STM32 MCUs - Application note

[JNguyen]

I'm able to send ALL_PIXELS_ON, ALL_PIXELS_OFF cmds to LCD repeatedly. LCD turns white and black repeatedly.

[JNguyen]

I already have memory reserve for Layer 0 - Color Frame Buffer Start Adress in MX_LTDC_Init() below:

static void MX_LTDC_Init(void)

{

 /* USER CODE BEGIN LTDC_Init 0 */

 /* USER CODE END LTDC_Init 0 */

 LTDC_LayerCfgTypeDef pLayerCfg = {0};

 /* USER CODE BEGIN LTDC_Init 1 */

 /* USER CODE END LTDC_Init 1 */

 hltdc.Instance = LTDC;

 hltdc.Init.HSPolarity = LTDC_HSPOLARITY_AL;

 hltdc.Init.VSPolarity = LTDC_VSPOLARITY_AL;

 hltdc.Init.DEPolarity = LTDC_DEPOLARITY_AH;

 hltdc.Init.PCPolarity = LTDC_PCPOLARITY_IPC;

 hltdc.Init.HorizontalSync = 3;

 hltdc.Init.VerticalSync = 3;

 hltdc.Init.AccumulatedHBP = 33;

 hltdc.Init.AccumulatedVBP = 33;

 hltdc.Init.AccumulatedActiveW = 513;

 hltdc.Init.AccumulatedActiveH = 833;

 hltdc.Init.TotalWidth = 531;

 hltdc.Init.TotalHeigh = 853;

 hltdc.Init.Backcolor.Blue = 0;

 hltdc.Init.Backcolor.Green = 127;

 hltdc.Init.Backcolor.Red = 0;

 if (HAL_LTDC_Init(&hltdc) != HAL_OK)

 {

   Error_Handler();

 }

 pLayerCfg.WindowX0 = 0;

 pLayerCfg.WindowX1 = 480;

 pLayerCfg.WindowY0 = 0;

 pLayerCfg.WindowY1 = 800;

 pLayerCfg.PixelFormat = LTDC_PIXEL_FORMAT_RGB565;

 pLayerCfg.Alpha = 0;

 pLayerCfg.Alpha0 = 0;

 pLayerCfg.BlendingFactor1 = LTDC_BLENDING_FACTOR1_CA;

 pLayerCfg.BlendingFactor2 = LTDC_BLENDING_FACTOR2_CA;

 pLayerCfg.FBStartAdress = 0;

 pLayerCfg.ImageWidth = 380;

 pLayerCfg.ImageHeight = 600;

 pLayerCfg.Backcolor.Blue = 0;

 pLayerCfg.Backcolor.Green = 0;

 pLayerCfg.Backcolor.Red = 0;

 if (HAL_LTDC_ConfigLayer(&hltdc, &pLayerCfg, 0) != HAL_OK)

 {

   Error_Handler();

 }

 /* USER CODE BEGIN LTDC_Init 2 */

 pLayerCfg.FBStartAdress = (uint32_t)Mushroom380x600;

 /* USER CODE END LTDC_Init 2 */

}

I also tried a small image (Mushroom380x600). The result is the same.

[MM..1]

pLayerCfg.FBStartAdress = (uint32_t)Mushroom380x600;
without call to init do nothing.
But primary change too
pLayerCfg.Alpha = 255;

[JNguyen]

From scope captures, I don't see data on RGB pins during active DE.

[JNguyen]

I tried below codes. It didn't help.

 /* USER CODE BEGIN LTDC_Init 2 */

 pLayerCfg.FBStartAdress = (uint32_t)Mushroom380x600;

 if (HAL_LTDC_Init(&hltdc) != HAL_OK)  Error_Handler();

 /* USER CODE END LTDC_Init 2 */

--------and -------

 /* USER CODE BEGIN LTDC_Init 2 */

 pLayerCfg.FBStartAdress = (uint32_t)Mushroom380x600;

if (HAL_LTDC_Init(&hltdc) != HAL_OK)  Error_Handler();

 if (HAL_LTDC_ConfigLayer(&hltdc, &pLayerCfg, 0) != HAL_OK)   Error_Handler();

 /* USER CODE END LTDC_Init 2 */

I also tried HAL_LTDC_DeInit(&hltdc) before HAL_LTDC_Init(&hltdc). It didn't help.

[JNguyen]

LTDC_IRQHandler(void) is never been called. I've been looking for reason why IRQ is not generated.

From scope captures, VSYNC and HSYNC are generated continuously. RGB data lines are 0x0.

[MM..1]

Try edit generated part before you understand howto...

static void MX_LTDC_Init(void)
{
 /* USER CODE BEGIN LTDC_Init 0 */
 /* USER CODE END LTDC_Init 0 */
 LTDC_LayerCfgTypeDef pLayerCfg = {0};
 /* USER CODE BEGIN LTDC_Init 1 */
 /* USER CODE END LTDC_Init 1 */
 hltdc.Instance = LTDC;
 hltdc.Init.HSPolarity = LTDC_HSPOLARITY_AL;
 hltdc.Init.VSPolarity = LTDC_VSPOLARITY_AL;
 hltdc.Init.DEPolarity = LTDC_DEPOLARITY_AH;
 hltdc.Init.PCPolarity = LTDC_PCPOLARITY_IPC;
 hltdc.Init.HorizontalSync = 3;
 hltdc.Init.VerticalSync = 3;
 hltdc.Init.AccumulatedHBP = 33;
 hltdc.Init.AccumulatedVBP = 33;
 hltdc.Init.AccumulatedActiveW = 513;
 hltdc.Init.AccumulatedActiveH = 833;
 hltdc.Init.TotalWidth = 531;
 hltdc.Init.TotalHeigh = 853;
 hltdc.Init.Backcolor.Blue = 0;
 hltdc.Init.Backcolor.Green = 127;
 hltdc.Init.Backcolor.Red = 0;
 if (HAL_LTDC_Init(&hltdc) != HAL_OK)
 {
 Error_Handler();
 }
 pLayerCfg.WindowX0 = 0;
 pLayerCfg.WindowX1 = 480;
 pLayerCfg.WindowY0 = 0;
 pLayerCfg.WindowY1 = 800;
 pLayerCfg.PixelFormat = LTDC_PIXEL_FORMAT_RGB565;
 pLayerCfg.Alpha = 255; //!!!
 pLayerCfg.Alpha0 = 0;
 pLayerCfg.BlendingFactor1 = LTDC_BLENDING_FACTOR1_CA;
 pLayerCfg.BlendingFactor2 = LTDC_BLENDING_FACTOR2_CA;
 //pLayerCfg.FBStartAdress = 0;
 pLayerCfg.FBStartAdress = (uint32_t)Mushroom380x600;
 pLayerCfg.ImageWidth = 480;
 pLayerCfg.ImageHeight = 800;
 pLayerCfg.Backcolor.Blue = 0;
 pLayerCfg.Backcolor.Green = 0;
 pLayerCfg.Backcolor.Red = 0;
 if (HAL_LTDC_ConfigLayer(&hltdc, &pLayerCfg, 0) != HAL_OK)
 {
 Error_Handler();
 }
 /* USER CODE BEGIN LTDC_Init 2 */
 
 /* USER CODE END LTDC_Init 2 */
}

[JNguyen]

I got the same result. LTDC IRQ is not generated. It's enable in CubeMX. Do you have any idea?

I issue ALL_PIXELS_ON/OFF commands, and LCD goes white/black. So LCD is init'ed correctly.

Scope capture shows CLK, HSYNC, DE, non-zero RGB.